Thyroid tumors of uncertain malignant potential: morphologic and imunohistochemical analysis of 29 cases.

INTRODUCTION: Thyroid tumors of uncertain malignant potential (TT-UMP) include follicular and well-differentiated tumors of UMP (FT-UMP/WDT-UMP), as it refers to the presence of questionable capsular/vascular invasion or incompletely developed papillary thyroid carcinoma (PTC)-type nuclear changes. However, these tumors are difficult to diagnose in most cases. We aimed to investigate whether immunohistochemistry (HBME-1, cytokeratin-19, galectin-3, CD56 and p63) provides additional information concerning such lesions. MATERIALS AND METHODS: We performed an immunohistochemical analysis on 29 TT-UMP cases (22 WDTs-UMP and 7 FTs-UMP) selected from the Rhone Alpes thyroid cancer registry and Departement of Pathology, Tîrgu-Mures Emergency County Hospital database. The clinicopathological and follow-up data were obtained. RESULTS: In the WDT-UMP group, HBME-1 was positive in 9/22 (40.9%) cases. CD56, a marker whose expression is reduced or absent in thyroid carcinoma, showed a "malignant" profile (no expression) in 13/22 (59.1%) cases. 7/22 (31.9%) cases were both HBME-1+ and CD56-. One case showed the co-expression of HBME-1, CD56, galectin-3 and cytokeratin-19. In the FT-UMP group, two cases were positive for HBME-1, other two for both galectin-3 and CK19 and only one case revealed a "malignant" CD56 profile. The follow-up data showed no distant metastases or persistent disease. CONCLUSION: Our study demonstrated very heterogeneous immunohistochemical profiles for TTs-UMP, further supporting the borderline nature of these lesions. WDTs-UMP revealed a certain tendency toward a PTC profile, suggesting a possible pathogeneticlink between these two entities. However, immunohistochemistry is still to be regarded more as a supporting diagnostic tool, while morphological criteria should always prime in the diagnostic decision.

Diagnostic value of HBME-1, CD56, Galectin-3 and Cytokeratin-19 in papillary thyroid carcinomas and thyroid tumors of uncertain malignant potential.

AIM: We aimed to evaluate four immunohistochemical markers (HBME-1, Galectin-3, Cytokeratin-19 and CD56) used alone or in panels in a series of papillary thyroid carcinoma (PTC) and thyroid tumors of uncertain malignant potential (TT-UMP) cases. MATERIALS AND METHODS: We performed an immunohistochemical analysis on a tissue micro-array of 11 PTCs [six classic (CPTC), five follicular variant (FVPTC)] and 31 TTs-UMP. A control group of 11 benign thyroid lesions/tumors was also included. RESULTS: CD56, whose expression is reduced or absent in thyroid carcinomas, was the most sensitive marker (81.8%), showing a "malignant" profile in 5/6 CPTCs and 4/5 FVPTCs. It was followed by HBME-1 (63.6% sensitivity). Cytokeratin-19 and Galectin-3 were the least sensitive antibodies (45.6%), but the most specific ones (100%). Three panels consisting of CD56 and/or Cytokeratin-19/Galectin-3 and HBME-1 and/or CD56 reached the highest sensitivity (90.9%) and the highest negative predicting value (87.5 and 83.3, respectively). In TTs-UMP, Cytokeratin-19, Galectin-3, HBME-1 and CD56 stained negatively in most of the cases (90.3%, 83.9%, 87.1% and 61%, respectively) and no statistically significant differences compared to the benign thyroid lesions' immunoprofile could be observed. CONCLUSIONS: New panels of antibodies, consisting of CD56 and/or Cytokeratin-19/Galectin-3 and CD56 and/or HBME-1 that were found to be highly sensitive for PTC in our study, are reported. Applying these panels to TTs-UMP seems also useful. Our results showed that these tumors have an immunoprofile similar to the benign thyroid lesions, suggesting that they are most likely to have a benign rather than a malignant biological behavior.

Thyroid cancer profile in Mures County (Romania): a 20 years study.

UNLABELLED: The aim of the present study was to present data on frequency of thyroid cancer in Mures County (Romania) and border counties, a goiter endemic area, and to analyze its histopathological characteristics, over a 20 years period (1990-2009). MATERIALS AND METHODS: Demographic, clinical and pathological data were obtained from database registries. Histological subtypes of thyroid cancer were classified according to the WHO criteria (sixth edition, 2004) in the following categories: papillary thyroid carcinoma with its histological subtypes, follicular thyroid carcinoma, poorly differentiated thyroid carcinoma, undifferentiated thyroid carcinoma, medullary carcinoma, lymphoma, metastatic tumors. RESULTS: Our analyze included 524 cases of thyroid cancer of the 3460 surgical thyroid specimens resected between 1990-2009: 410 (78.2%) cases of papillary carcinoma, 19 (3.6%) cases of follicular carcinoma, 24 (4.6%) cases of poorly differentiated carcinoma, 33 (6.3%) cases of undifferentiated carcinoma, 22 (4.1%) medullary carcinomas, eight (1.6%) lymphomas, and eight (1.6%) metastatic tumors. Papillary thyroid carcinoma is the most common histological form (78%) and an increasing incidence of this form was observed. A statistical significant increase in the incidence of the follicular variant of papillary carcinoma was noticed between 2000-2009, compared to 1990-2000. An increased incidence of small tumors was also found (6.66%, 1990-1999 vs. 23.5%, 2000-2009). The undifferentiated thyroid cancer had a marked decreasing trend (20%, 1990-1999 vs. 3.45%, 2000-2009). CONCLUSIONS: Our study demonstrates an increasing trend in the incidence of thyroid cancer in the last 20 years. This increase is mainly due to the small papillary cancers, by contrast to the undifferentiated thyroid cancers that have a decreasing trend. A better understanding and description of the morphological criteria could explained the increasing incidence of the follicular variant of papillary carcinoma.